Chem 51 LB Experiment 3 Report Scaffold: Bromination of Trans-Cinnamic Acid 1. The goal of this experiment was to perform a halogenation reaction through the addition of two bromides from pyridinium tribromide. This was accomplished by reacting trans-cinnamic acid with pyridinium tribromide. After the reaction took place, melting point analysis was conducted to find out the stereochemistry of the product, which could either be syn-addition, anti-addition, or syn + anti-addition. 2. Vacuum filtration was performed on the crude product, then it was recrystallized for purification. Melting point analysis was conducted on the recrystallized product to determine its identity. 3. The three possible mechanisms in this experiment were syn-addition …show more content…
The product obtained was (2S, 3R)-2, 3-dibromo-3-phenylpropanoic acid and (2R, 3S)-2, 3-dibromo-3-phenylpropanoic acid, which are enantiomers. This was determined through melting point analysis. The melting point range for the product was 198 to 202 degrees Celsius, which is a lot close to the given melting point of the anti-addition product, 202-204 degrees Celsius. The given melting point range was 93.5-95 degrees Celsius. Furthermore, the syn-addition product is unlikely and difficult to produce due to stereochemistry selectivity. 9. The melting point range was lower than the given range of the anti-addition product by 2 degrees Celsius. This could have been due to impurities in the product. A likely cause could have been water that still remained in the product after recrystallization (the product shifted upward during melting point analysis due to evaporation). Since water has a low melting point, it could have lowered the melting point range of the product. However, 2 degrees Celsius is not extremely significant to pronounce inconclusiveness of the …show more content…
Yes, the melting point data does make sense. While the melting point range was close to the given temperature range, the data was still a little lower than expected. This may have been caused by impurities in the product, since impurities cause melting point range to decrease. The product was observed moving up the capillary tube during melting point analysis, which indicates that the product was not completely dry before melting point range was taken. The water in the product evaporated and caused the product to be pushed up. It can be hypothesized that the water in the product affected the melting point
Many sources of error were responsible for recovering a small amount of product. Introduction: The carbon-carbon bond formation is an important tool in organic chemistry to construct the simple as well as an organic compound. There are several
Since water and magnesium bromide chloride was structured as side products after the adduct was hydrolyzed, the product was isolated using two separate extractions: an ether extraction and an aqueous extraction through a separatory funnel. The product was then purified using petroleum ether and recrystallized using boiling isopropyl
Because of this, three different products (as previously mentioned) are potentially formed.1 The compound created from the reaction can be analyzed to determine
It forms a complex with HBr and extracts it from the aqueous phase into the organic phase where the alkene is. This dehydrates the acid, making it more reactive so that the addition reaction is possible. Rapid stirring is required in order to maximize the surface area
The purpose of this experiment was to learn about the electrophilic aromatic substitution reactions that take place on benzene, and how the presence of substituents in the ring affect the orientation of the incoming electrophile. Using acetanilide, as the starting material, glacial acetic acid, sulfuric acid, and nitric acid were mixed and stirred to produce p-nitroacetanilide. In a 125 mL Erlenmeyer flask, 3.305 g of acetanilide were allowed to mix with 5.0 mL of glacial acetic acid. This mixture was warmed in a hot plate with constantly stirring at a lukewarm temperature so as to avoid excess heating. If this happens, the mixture boils and it would be necessary to start the experiment all over again.
Purpose: The purpose of this experiment was to determine the molar mass of unknown #43 using the derived freezing point depression. To obtain the freezing point depression, t-butyl alcohol was placed in a cold-water bath and frozen solid for a total of two runs. Then, unknown #43 was dissolved in t-butyl alcohol and placed in a cold-water bath until frozen solid. This process was repeated for a total of three runs, with the first two runs containing half of the unknown, and the last run containing the full amount of unknown.
The powder on the filter paper could've fell and this caused it to have a smaller percent purity, percent yield and also cause a lower absorbance and concentration of pure ASA. Another error would be not using a properly dried sample for the pure ASA in part C when making the crystals, this could have cause tye percent yield error. This would make a lower melting point. To prevent this from occurring next time there could be a dry sample that is completely dry and this would not alter the mass of the sample and this would make the solution have a more
Errors could have come from the ice bath not being cold enough, not all the powder transferred into the 11 dram vial, and not dissolving all of the powder. The usage of tap water instead of distilled water would have affected the results for tap water contains other ions which would then affected the freezing point depression. Salting icy roads and walkways lowers the freezing point of the water that forms ice which leads to melting and prevents falling snow or rain from being able to freeze.
The substitution reaction was successful but not fully effective. 19. If the data was inconclusive, then comparing various compounds and the unknown based on physical characteristics would be the first step, titrations would also be a good method. 20. To get a better yield, redoing the experiment would require careful attention in the recrystallization steps: amount of solvent used, how hot solvent is, if the mixture cools to room temperature before placing it in an ice
The literature melting point range of methyl trans-cinnamate is ~34-38oC (Aldrich).4 The obtained melting point of the crude was 34.5-35.5oC, which is a highly narrow range of less than 1oC difference and it also falls within the expected melting point range. Hence, the crystal lattice structure of the product is largely intact, requiring an even amount of thermal energy to melt the sample. The experimental melting point range indicates the crude product is relatively pure with minimal impurities. The percent yield was satisfactory, having a 68% yield. To optimize this yield, consider the steps in how the reagents are introduced to the reaction mixture in terms.
The results from most of the experiment best fit with Potassium chloride, although not all the test fit with potassium chloride. For example, in “Part A” When the salt was put in the flame it made the flame turn violet. This supports the conclusion that the salt is potassium chloride because potassium chloride also makes a violet flame when burned. The flame test was the most conclusive test because all 8 of the possible salts that were given have very significant flame color. None of the other salts have a violet color flame when burned which goes to prove that the salt is potassium chloride.
Purpose/Introduction The process of recrystallization is an important method of purifying a solid organic substance using a hot solution as a solvent. This method will allow the separation of impurities. We will analyze Benzoic Acid as it is dissolved and recrystallized in water and in a solvent of Methanol and water. Reaction/Summary
8. RESULTS AND DISCUSSION 8.1 PREFORMULATION STUDIES 8.1.1 Characterization of Oxubutynin chloride 8.1.1.1 Organoleptic properties The sample of OXB was found to be a white crystalline practically odourless powder. 8.1.1.2 Melting point
Furthermore, this compound has the density 1.244 which conveys that it is denser than water. As comparison, It’s melting point range from 157℃ up until
Pomegranate has various health beneficial properties, mainly antioxidants and antimicrobial. The inedible pomegranate rinds contain about 50% of the total fruit weight and it contain various bioactive compounds such as phenolics, flavonoids, ellagitannins (ETs), and proanthocyanidin compounds(Li et al., 2006), minerals, mainly potassium, nitrogen, calcium, phosphorus, magnesium, and sodium (Mirdehghan and Rahemi, 2007), and complex polysaccharides (Viuda-Martos et al., 2010). The edible pomegranate fruit (50%) consists of 40% arils and 10% seeds (Viuda-Martos et al., 2010). Arils contain 85% water, 10% total sugars, mainly fructose and glucose, and 1.5% pectin, organic acid such as ascorbic acid, citric acid, and malic acid, and bioactive